Research Of Link Adaptation Technology In B3G System

The next generation of cellular mobile communication system is required to support various applications, from the high quality of interactive Real-time traffics (such as voice and video communications) to the reliable services based on TCP link. For the current wireless network, the increment of user's application requests result in unbalance usage with the wireless bandwidth. Try to resolve the problem of QoS(quality-of-service) requirements of new generation of cellular mobile communication system is to utilize the limited bandwidth reasonably and guarantee the QoS that every kind of applications transmitting in the network, meanwhile provide the lower spending of operation and management. Then we can assure the development of new applications in new generation of wireless communication system. In fact, wireless bandwidth is certainly the most valuable resource. How to increase the data transmitting rate furthest in limited wireless bandwidth, in another word, how to enhance the efficiency of utilizing the wireless bandwidth at maximum has been the key to utilize the wireless resources reasonably. This article introduced the construction frame which can support QoS in the new cellular mobile communication system, and did some new research on the hot field of data-link layer adaptation in wireless mobile system based on improved ARQ platform, and proposed a new high-speed algorithm of data-link adaptation united physical layer with data-link layer. In the end we validated the protocols and algorithms with the software of OPNET Modeler. From the result of emulating we could find that under the term of limited bandwidth, this algorithm would get good use of limited wireless resources in wireless channel and decrease loads of ARQ in MAC(Media Access Control) layer. At the same time it could really ensure high throughput under different channel conditions and also resists outburst of error in channel. The method of dynamic data-link adaptation has been adopted in project 5.8G broadband wireless access system. The research and practice prove it a portable solution and applicable in various wireless situations.